Easy-opening stopper for metal cans and the like

ABSTRACT

An easy-opening cover for cans wherein the cover is made with an opening hermetically sealed by a stopper formed of a plastic material and molded in situ and retained in position of use by a movable lip extending downwardly from the underside of the stopper at a position located beneath the edge of the can about the opening.

United States Patent Cospen et a1.

[15] 3,682,349 51 Aug. 8, 1972 [54] EASY-OPENING STOPPER FOR METAL CANS AND THE LIKE [72] Inventors: Jean Cospen, 2 rue de LYser, 94-

Cachan; Bernard Baumann, 15 avenue de Friedland, 75-Paris 8th, both of France [22] Filed: July 6, 1970 [21] Appl. No.: 52,273

301 Foreign Application Priority Date:

[58] Field of Search..52/584, 400; 53/329; 220/42 B, 220/43 A, 47, 24 A, 24 H, 24.5, 38.5, DIG.

Peyser ..220/54 X 4/1969 3,473,692 10/1969 'Moller .220/47 3,133,666 5/1964 Henchert. ..220/24.5 X 3,107,838 10/1963 Brys et a1 ..220/42 B X 3,021,976 2/1962 Tracy ..220/42 8 X 2,848,130 8/1958 Jesnig ..215/52 X 3,106,311 10/1963 Fairchild ..220/38.5 X

Primary Examiner-Raphael H. Schwartz Attoniey-McDougall, Hersh & Scott 57 ABSTRACT An easy-opening cover for cans wherein the cover is made with an opening hermetically sealed by a stopper formed of a plastic material and molded in situ and retained in position of use by a movable lip extending downwardly from the underside of the stopper at a position located beneath the edge of the can about the opening.

12 Claims, 9 Drawing Figures 561 References Cited I UNITED STATES PATENTS 3,428,212 2/1969 Rohrlick ..220/60 PATENTEDAuc 8 I972 SHEET 2 BF 4 Fig. 5

Fig. 9

EASY-OPENING STOPPER FOR METAL CANS AND THE LIKE This invention relates to an easy-opening closure or stopper for metal cans or the like.

It is becoming increasingly common to preserve beverages and the like food products in metal cans. This form of packaging has a number of advantages over the conventional glass bottle such as being lighter in weight and less fragile. However, problems exist insofar as an opening for access to the content material is concerned since it should be easy to open without the need to make use of special tools.

With this objective in view, ithas heretofore been proposed to make use of covers having a surface provided with a tear strip, usually consisting of the same material as the cover itself, and having a tab which is generally fixed to the tear strip by an integral rivet. The tensile strength of the rivet used to fix the tear strip and the uniformity of tear are frequently unsatisfactory, with the result that the cover has been manufactured with a cutout in which a plastic stopper, provided with a tab, is inserted. In instances where the tear line is situated on the cover, the stopper replaces the rivet. If the tear line is situated on the stopper itself, the opening is formed in the stopper. Unfortunately, these embodime'nts give rise to sealing problems which are very difficult to overcome, especially when packaging beverages under gas pressure.

It is an object of this invention to eliminate these deficiencies by providing a hermetically sealed closure which can be removed with minimum effort.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments of the invention are shown in the accompanying drawings in which FIG. 1 is a sectional elevational view taken along the center of a cover embodying the features of this inventron;

F IG. 2 is a top plan view of the cover shown in FIG. 1;

FIG. 3 is a sectional elevational view through a stopper provided with reinforcing ribs;

FIG. 4 is a sectional elevational view through a stopper provided with notches;

FIG. 5 is a sectional elevational view through a stopper having a reinforced center and a peripheral groove of variable depth;

FIG. 6 is a sectional view showing the stopper in position of use on the cover;

FIG. 7 is a sectional view of the stopper in FIG. 6 at an intermediate stage of removal;

FIG. 8 is a sectional view of the stopper shown in FIGS. 6 and 7 in a further advanced stage of removal; and

FIG. 9 is a top plan view of a cover embodying the features of this invention with two openings.

The invention relates to an easy-opening closure for metal cans or the like manufactured with an opening in the cover which is hermetically sealed by a plastic stopper molded in situ and retained by a displaceable internal disappearing lip.

The stopper is molded in situ under known temperature and pressure conditions, for example by injection molding, by direct pressure molding, or by the total or partial molding of a preform, etc. The material used is a plastic, preferably a polypropylene.

The movable disappearing lip rests on the inner surface of the cover along the edge of the opening to be plugged and extends in a general direction substantially perpendicular to this surface. When the can is opened, the movable lip is caused to rotate about an articulation zone which will hereinafter be defined, its upper side stopping substantially perpendicularly of the edge of the opening to enable the cover to be removed without tearing any of the material.

A second fixed lip is situated concentrically with the movable lip towards the center of the stopper. The oppositesurfaces of the two lips may be flat, broken or curved. The lips define a groove therebetween which may vary in width and which may vary in depth, depending upon the degree of stiffness desired to be imparted to the articulation zone. The shape of the groove should enable the movable lip to rotate or rock about the articulation zone through an angle of at least without interference by the fixed lip.

The size of the fixed lip is also variable depending upon the requirements. It can be shrunk into a central inner reinforcement or omitted altogether in certain special cases.

The articulation zone isdetermined by a number of parameters: the distance between the starting point of the inner surface of the movable lip on the one hand and the edge of the opening of thecover on the other hand; the shape of the movable lip; the width of the groove; the mass of the fixed lip or central reinforcement, if present. By varying these different parameters, it is possible to use plastic materials differing widely in grade to obtain the desirable effects.

The depth of the groove separating the two lips can vary about its periphery, the effect of which is to graduate the effort required to remove the stopper.

To make the stopper easy to remove, once the movable lip has been initially displaced, the base of the stopper can be provided with parallel outer and/or inner notches, optionally staggered over the two surfaces. By contrast, the stiffness of the stopper can be increased by ribs on the central outer portion.

The stopper is provided externally with a grip member in the form of a tab, usually terminating in a ring or other readily gripped configuration.

In instances where a liquid is to be packaged under pressure, such for example as beer, it can be advantageous to provide the cover with a second opening of smaller diameter than the main opening and which is plugged in substantially the same manner as the main opening, optionally with a modification of the articulation zone. The-two stoppers are connected together by a bridge and the finger grip should be fixed to the stopper first to be removed. 2 The configuration of the lips allows an almost unlimited variation of shapes without departing from the scopeof the invention.

With reference now to the drawings, the dimensions of the covers are highly exaggerated and do not necessarily show the true dimensional relationships.

InFIG. l, the cover 1 has an opening which is closed by the stopper 2. The stopper consists of a diaphragm 3 surrounded by a reinforcing edge 4 of greater crosssectional thickness, and having an outer wall formed with a recessed portion 10" in which the free edge 10 of the cover 1 is inserted level with the diaphragm 3. The reinforced edge 4, when viewed from the interior of the can, has a groove 5 which separates an outer movable lip 6 from a spaced inner fixed lip 7. The part 8 of the reinforcing edge 4 which is situated above the level of the cover 1 is provided with a grip tab, such as tab 9, extending from the side of a tab 9' extending upwardly from the top surface.

A connecting strip or bridge 12 connects the inner edge'of the stopper 2 with a second stopper 18 of the same general construction, which is used when two openings are provided in the cover.

The stopper is formed of a plastic material, preferably a polypropylene, which is unaffected by the content material in the can.

The free edge of the cover I can be curved normally upwardly, as at 11, to take into consideration contraction of the plastic material during formation of the stopper into a preferential zone which enables the plastic material to be Stopped at the raised edge and contributes towards increasing the fluid-tightness of the closure.

FIG. 3 shows a stopper which can be removed in one go. The central portion 3 is reinforced by a rib 13 which extends upwardly from the surface in laterally spaced apart relation with the reinforced edge and which, in the example shown, is circular but can be any other form. The stiffening effect produced by the rib or ribs results in immediate detachment of the stopper around its entire periphery when the can is opened.

If the product contained in the can does not have internal pressure and gradual opening is required, the central diaphragm can advantageously be provided with a series of spaced notches 14 on one side or on both sides of the diaphragm portion intermediate the reinforced edge of the stopper. In the latter case, the notches can be provided opposite one another or, in the alternative, they can be staggered relative to one another in the respective surfaces, as shown in FIG. 4.

Another possibility of obtaining gradual opening is illustrated in FIG. 5. In this modification, the diaphragm is highly reinforced with the diaphragm portion having a thickness which can be equal to that of the reinforcing edge. The groove which separates the movable lip 6 from the central inner portion 17, which in this modification replaces the fixed lip 7, is variable in depth around the periphery, gradually diminishing from a maximum depth in the portion 15, where the tear tab 9 is situated, to a minimum depth at the portion 15' situated diametrically opposite.

In FIGS. 6-8, illustrating the different phases involved in the removal of a stopper, the fixed lip has been replaced by a central downwardly extending reinforcement and the upper portion 3 above the can line is substantially the same in the middle as at the edge. FIG. 6 illustrates the closure in position of use on the can.

To begin opening, the tap 9 is gripped by the user and pulled upwardly. In response to this pull, the movable lip 6 begins to turn about its articulation zone into the groove 5 in the direction towards the fixed lip 7. As the applied force increases, the surface 6' which was in contact with the underside of the edge of the cover 1 gradually moves to a position perpendicular to its starting position, as illustrated in FIGS. 7 and 8.

Finally, as shown in FIG. 8, the surface has completed its rocking movement about the edge of the cover and the stopper can be completely disengaged by displacement through the opening.

In this disengaged position, the movable lip has rejoined the central reinforcement 17, the edge 17 of which is designed in such a way as not to interfere with the complete turning of the lip.

A cover with two openings is shown in FIG. 9. A large stopper 2 plugs the opening from which the content material is poured from the can while a smaller stopper l8 plugs the opening through which air can be admitted during removal of the stopper and while content material is being poured from the can. The two stoppers 2 and 18 are joined by a bridging strip 12 with the tab 9 extending from the small stopper to a grip member 19 in the form ofa ring.

It will be understood that changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

1. In a container having a cover with an opening, a removable stopper for hermetically sealing the opening formed of a stiff plastic material molded in situ and dimensioned to span the opening and extend a short distance beyond the opening with the stopper having a central body portion and an outer reinforcing portion, a top side facing outwardly of the container and a bottom side facing inside the container, a recessed portion extending inwardly from the outer edge of the stopper in which the edge of the cover about the opening is received in sealing relation, a movable lip extending downwardly from the bottom side of the stopper underlying the edge of the cover for articulation about the edge of the cover in response to an upwardly directed force, a fixed lip extending from the bottom side and spaced laterally inwardly from the movable lip members to define a groove between the movable lip and the fixed lip into which the movable lip is displaced about the edge of the opening in response to a force applied for removal of the stopper, and a tab extending from the outer reinforced portion of the stopper above the recessed portion for application of force to remove the stopper.

2. A stopper as claimed in claim 1 which is integrally molded of a polypropylene plastic.

3. A stopper as claimed in claim 1 in which the movable lip rests on the inner surface of the cover along the edge of the opening and extends in a general direction substantially perpendicular to the surface.

4. A stopper as claimed in claim 1 in which the groove varies in depth and/or in width.

5. A stopper as claimed in claim 1 in which the fixed lip comprises a central reinforcement section of greater thickness.

6. A stopper as claimed in claim 4 in which the groove varies in depth from a maximum depth adjacent the tab to a minimum depth opposite the tab.

7. A stopper as claimed in claim 1 which includes one or more notches in the top side and/or the bottom side of the stopper.

8. A stopper as claimed in claim 7 in which the notches are in both the top side and bottom side surfaces of the stopper withthe notches arranged one over the other.

second opening and a stopper as claimed in claim 1 for said second opening.

12. A cover as claimed in claim ll which includes a bridging strip joining the stoppers and a grip tab joined to the edge of the second stopper.

UNITED STATES PATENT OFFICE CERTIFICATE OF COREQTION August a, 1972 Patent No. 3 682 349 Dated lnventofls) Jean Cospen; Bernard Baumann It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Assignee: CEBAL GP, Paris, France Signed and sealed this 8th day of May 1973" (SEAL) Attest:

EDL-JARD MELETCHERJR. I ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-105O (10-69 UScOMM-DC 60376-P69 Q u.s, sovnmum' murmur, omcs; I969 o-sss-au 

1. In a container having a cover with an opening, a removable stopper for hermetically sealing the opening formed of a stiff plastic material molded in situ and dimensioned to span the opening and extend a short distance beyond the opening with the stopper having a central body portion and an outer reinforcing portion, a top side facing outwardly of the container and a bottom side facing inside the container, a recessed portion extending inwardly from the outer edge of the stopper in which the edge of the cover about the opening is received in sealing relation, a movable lip extending downwardly from the bottom side of the stopper underlying the edge of the cover for articulation about the edge of the cover in response to an upwardly directed force, a fixed lip extending from the bottom side and spaced laterally inwardly from the movable lip members to define a groove between the movable lip and the fixed lip into which the movable lip is displaced about the edge of the opening in response to a force applied for removal of the stopper, and a tab extending from the outer reinforced portion of the stopper above the recessed portion for application of force to remove the stopper.
 2. A stopper as claimed in claim 1 which is integrally molded of a polypropylene plastic.
 3. A stopper as claimed in claim 1 in which the movable lip rests on the inner surface of the cover along the edge of the opening and extends in a general direction substantially perpendicular to the surface.
 4. A stopper as claimed in claim 1 in which the groove varies in depth and/or in width.
 5. A stopper as claimed in claim 1 in which the fixed lip comprises a central reinforcement section of greater thickness.
 6. A stopper as claimed in claim 4 in which the groove varies in depth from a maximum depth adjacent the tab to a minimum depth opposite the tab.
 7. A stopper as claimed in claim 1 which includes one or more notches in the top side and/or the bottom side of the stopper.
 8. A stopper as claimed in claim 7 in which the notches are in both the top side and bottom side surfaces of the stopper with the notches arranged one over the other.
 9. A stopper as claimed in claim 7 in which the notches in the top side are staggered with respect to the notches in the bottom side.
 10. A stopper as claimed in claim 1 which includes reinforcing ribs extending upwardly from the top side of the stopper.
 11. A cover as claimed in claim 1 which includes a second opening and a stopper as claimed in claim 1 for said second opening.
 12. A cover as claimed in claim 11 which includes a bridging strip joining the stoppers and a grip tab joined to the edge of the second stopper. 